/Engine/Plugins/FX/Niagara/Source/Niagara/Public/NiagaraTypes.h
enum ENiagaraTypeRegistryFlags { None = 0, AllowUserVariable = (1 << 0), AllowSystemVariable = (1 << 1), AllowEmitterVariable = (1 << 2), AllowParticleVariable = (1 << 3), AllowAnyVariable = (AllowUserVariable | AllowSystemVariable | AllowEmitterVariable | AllowParticleVariable), AllowParameter = (1 << 4), AllowPayload = (1 << 5), IsUserDefined = (1 << 6), }